The present invention relates, according to a first aspect, to a toy brick comprising:                A body part with one or more sidewalls extending around the outer periphery of the toy brick. The one or more sidewalls at least partially define an interior of the toy brick and the sidewalls extend from a bottom face to a top portion of the body part,        An elongated rib arranged interiorly in the body part. The elongated rib extends essentially between the bottom face towards the top portion of the body part,        A width of the elongated rib, in an end portion near the top portion and parallel to a portion of a face accommodating the elongated rib, which width near the top portion is greater than or equal to the width of the elongated rib near its end, facing the bottom face.        
The body part may form part of a complex toy brick and the like.
The elongated rib may constitute a raised ridge or similar projecting from a surface such as a wall or an internal pipe etc. The elongated rib may serve multiple purposes such as to contribute to structural integrity of an item or to contribute to functional properties of an item.
According to a second aspect, the present invention relates to a method of manufacturing a toy brick.
According to a third aspect, the present invention relates to a moulding tool for manufacturing a toy brick.
According to other aspects, the present invention relates to a plastic product or item, a method of manufacturing a plastic product and a moulding tool for manufacturing a plastic product.
WO 2010/145660 A discloses a building element, a method of making a building element and a moulding tool for the manufacture of a building element. The building element constitutes a building brick including sidewalls that are undercut at least in an area where the brick abut on a coupling stud of another building brick. The undercut is located a distance from the lower-most edge corresponding to the height of the coupling stud of the other building brick. This to the effect that the complementarily configured surfaces adjoin the cylinder faces on coupling stud at least a distance below the top of the coupling stud. By this, a building element which takes into account the wish for a stable and adequate retention force, while simultaneously it is simple and easy to interconnect with other building elements.
U.S. Pat. No. 8,105,128 B1 discloses an injection moulded toy building element which in its interior has at least one hollow member which is open through the extended upper surface, and has an outward slope, in a direction extending from the bottom towards the top. The purpose of the hollow member being open to the extended upper surface is to facilitate the formation of the hollow member and the removal thereof from the mould parts.
Building elements of the type according to an aspect of the present invention advantageously are manufactured by a method that comprises injection moulding in two or more steps. The method includes an injection moulding step wherein the building element typically is injection moulded in one overall moulding step.
The building element may be injection moulded in a mould cavity with an internal mould space having a shape that corresponds to the outer shape of the building element. The mould typically constitutes a two part mould where one part of the mould defines the underside, or the interior, of the building element and the other part of the mould defines the upper face and the exterior of the building element.
The building element is moulded by means of injecting hot material into the compiled moulds and subsequently, when various parameters such as temperature reach a predetermined range, separating the moulds.
Upon separation of the moulds, and subsequent removal of the element from one of the mould parts, the building element typically constitutes a finished product.
In order to control large scale manufacture of injection moulded items such as manufacture of building elements made of plastic, removal of the item or items from the mould may involve several steps of high sophistication. Typically, the items as well as one or more of the moulds, are designed to, upon separation of the moulds; maintain the item on or in the same mould part upon separation of the moulds.
The mould part on or in which the item is designed to stay or reside upon mould separation, typically is provided with means configured for removing or detaching the item from the mould. The means may constitute a mechanical ejector or equivalent. Up to this day, items such as toy bricks and the like typically are produced by injection moulding, and the items often includes one or more barbs or protrusions having the sole purpose of maintaining the item on the same part of the mould when the mould parts are separated. During subsequent removal of the item from the mould part on or in which the item resides, the barbs are, by means of an ejector and sometimes also assisted by a ramp effect caused by shrinkage of the item during cooling, forced out of a cavity in the mould part shaping the barb. This method may damage the items as the items are exposed to sometimes violent and unevenly distributed forces during ejection from the mould.
The damages may constitute cosmetic as well as mechanical damages.